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Asymmetric Quantum Well Structures For Enhanced Infrared Photon Absorption
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Book Synopsis Asymmetric Quantum Well Structures for Enhanced Infrared Photon Absorption by : Mehjabeen Akhtar Khan
Download or read book Asymmetric Quantum Well Structures for Enhanced Infrared Photon Absorption written by Mehjabeen Akhtar Khan and published by . This book was released on 2013 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compared to inter-band transition for photon absorption in a quantum wells, intra-band (or inter-subband) transitions in heterojunction (GaAs/InP) quantum wells can provide access to a broader range of wavelengths for detector design, specifically detectors operating in the mid infrared region of spectrum (4-12 [micro]m) and beyond is possible. These quantum wells not only provide great flexibility in optimizing the Eigen energy levels or wavefunctions, and inter-subband optical matrix elements determining the corresponding transition probability, but also allow controlling electron-phonon scattering rates and thus electron lifetime. The research presented in this dissertation investigates asymmetric quantum well structures formed through III-V semiconductor material system such as AlGaAs/ InxGa(1-x)As/InyGa(1-y) As/AlGaAs that can further improve the responsivity through higher carrier mobility. Asymmetry is introduced by using multiple materials to form the well region. The advantage of exploring stepped quantum well structure stems from experimental evidence that such structures are capable of absorbing normal incidence and thus eliminates the requirement of incorporating additional optical coupling schemes such as grating structures. An important contribution of this research is the development of an analytical model to analyze single or multiple quantum well structures to quantify photon absorption. The physical model developed in this work is based on non-equilibrium Green's function (NEGF), Fermi's golden rule and quantum mechanical wave impedance concept. The approach has two distinct advantages. First, it is accurate, easily programmable and yet computationally efficient. Second, it facilitates quantifying the broadening of states resulting from both photon absorption and tunneling, which provides important insight for improving detection efficiency. Instead of being presented through calculations, such broadening has been simply assumed in previously reported works. The method developed in this research provides an efficient methodology to quantify the absorption rate of photons with different polarizations. The study looks into the design and analysis of the wells to enhance infrared radiation detection, and suggests mechanisms to optimize the structures in terms of material choice, composition, structural geometry and applied voltages. The high electron mobility and hence drift velocity in InGaAs ( >5×106cm/s), along with low carrier recapture lifetime, is expected to improve the detection speed of the device. Unlike GaAs/AlGaAs, the lattice mismatch at InGaAs/AlGaAs interface is likely to introduce strain in the structure. The effect of such strain as well as the layer thickness is taken into account in this work. Also, a methodology for achieving voltage tenability, i.e. the ability to detect different wavelengths at different bias voltages has been investigated. Although both n-type and p-type systems have potential for optoelectronic devices, n-type quantum wells are more advantageous because of their nearly parabolic sub-band structure. As for material consideration, direct band gap material based systems, such as AlGaAs/InGaAs and AlGaAs/GaAs, have been found to be particularly suitable for n-type QWIP photodetectors. The reason being that the electrons in such materials occupy states around the [gamma]valley where the effective mass is smaller and therefore mobility is higher; a condition which leads to higher photoresponsivity. Moreover such systems allow the possibility of highly stable device operation owing to the insensitivity of intra-band transition energies to temperature fluctuation and reduced influence of Auger recombination.
Book Synopsis Quantum Well Intersubband Transition Physics and Devices by : Hui C. Liu
Download or read book Quantum Well Intersubband Transition Physics and Devices written by Hui C. Liu and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 573 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intersubband transitions in quantum wells have attracted tremendous attention in recent years, mainly due to the promise of applications in the mid and far-infrared regions (2--20 mum). Many of the papers presented in Quantum Well Intersubband Transition Physics and Devices are on the basic linear intersubband transition processes, detector physics and detector application, reflecting the current state of understanding and detector applications, where highly uniform, large focal plane arrays have been demonstrated. Other areas are still in their early stages, including infrared modulation, harmonic generation and emission.
Book Synopsis Intersubband Transitions in Quantum Wells by : Emmanuel Rosencher
Download or read book Intersubband Transitions in Quantum Wells written by Emmanuel Rosencher and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the lectures delivered at the NATO Advanced Research Workshop on the "Intersubband Transistions in Quantum Wells" held in Cargese, France, between the t 9 h and the 14th of September 1991. The urge for this Workshop was justified by the impressive growth of work dealing with this subject during the last two or three years. Indeed, thanks to recent progresses of epitaxial growth techniques, such as Molecular Beam Epitaxy, it is now possible to realize semiconductor layers ( e.g. GaAs) with thicknesses controlled within one atomic layer, sandwiched between insulating layers (e.g. AlGaAs). When the semiconducting layer is very thin, i.e. less than 15 nm, the energy of the carriers corresponding to their motion perpendicular to these layers is quantized, forming subbands of allowed energies. Because of the low effective masses in these semiconducting materials, the oscillator strengths corresponding to intersubband transitions are extremely large and quantum optical effects become giant in the 5 - 20 ~ range: photoionization, optical nonlinearities, ... Moreover, a great theoretical surprise is that - thanks to the robustness of the effective mass theory - these quantum wells are a real life materialization of our old text book one-dimensional quantum well ideal. Complex physical phenomena may then be investigated on a simple model system.
Book Synopsis Confined Electrons and Photons by : Elias Burstein
Download or read book Confined Electrons and Photons written by Elias Burstein and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt: The optical properties of semiconductors have played an important role since the identification of semiconductors as "small" bandgap materials in the thinies, due both to their fundamental interest as a class of solids baving specific optical propenies and to their many important applications. On the former aspect we can cite the fundamental edge absorption and its assignment to direct or indirect transitions, many-body effects as revealed by exciton formation and photoconductivity. On the latter aspect, large-scale applications sucb as LEDs and lasers, photovoltaic converters, photodetectors, electro-optics and non-linear optic devices, come to mind. The eighties saw a revitalization of the whole field due to the advent of heterostructures of lower-dimensionality, mainly two-dimensional quantum wells, which through their enhanced photon-matter interaction yielded new devices with unsurpassed performance. Although many of the basic phenomena were evidenced through the seventies, it was this impact on applications which in turn led to such a massive investment in fabrication tools, thanks to which many new structures and materials were studied, yielding funher advances in fundamental physics.
Book Synopsis Giant Enhanced Four-wave Mixing Efficiency Via Two-photon Resonance in Asymmetric Quantum Wells by :
Download or read book Giant Enhanced Four-wave Mixing Efficiency Via Two-photon Resonance in Asymmetric Quantum Wells written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ultrafast Phenomena in Semiconductors by : Kong-Thon Tsen
Download or read book Ultrafast Phenomena in Semiconductors written by Kong-Thon Tsen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are many books in the market devoted to the review of certain fields. This book is different from those in that authors not only provide reviews of the fields but also present their own important contributions to the fields in a tutorial way. As a result, researchers who are already in the field of ultrafast dynamics in semicon ductors and its device applications as well as researchers and graduate students just entering the field will benefit from it. This book is made up of recent new developments in the field of ultrafast dynamics in semiconductors. It consists of nine chapters. Chapter 1 reviews a mi croscopic many-body theory which allows one to compute the linear and non-linear optical properties of semiconductor superlattices in the presence of homogeneous electric fields. Chapter 2 deals with ultrafast intersubband dynamics in quantum wells and device structures. Chapter 3 is devoted to Bloch oscillations in semicon ductors and their applications. Chapter 4 discusses transient electron transport phe nomena, such as electron ballistic transport and electron velocity overshoot phe nomena as well as non-equilibrium phonon dynamics in nanostructure semicon ductors. Chapter 5 reviews experimental and theoretical work on the use of the phase properties of one or more ultrashort optical pulses to generate and control electrical currents in semiconductors.
Book Synopsis Asymmetric Quantum Well Structures by : Craig Cooper
Download or read book Asymmetric Quantum Well Structures written by Craig Cooper and published by . This book was released on 1997 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Long Wavelength Infrared Emitters Based on Quantum Wells and Superlattices by : Manfred Helm
Download or read book Long Wavelength Infrared Emitters Based on Quantum Wells and Superlattices written by Manfred Helm and published by CRC Press. This book was released on 2000-10-31 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a thorough survey of long wavelength infrared semiconductor emitters based primarily on quantum wells and superlattices. Featuring contributions from the most prominent researchers in the field, this volume allows readers to compare different types of lasers as well as examine investigations of potential far-infrared/terrahertz sources. This is an essential reference for researchers, engineers and graduate students who wish to obtain comprehensive knowledge about infrared semiconductor sources and recent developments in this field.
Book Synopsis Quantum Wells, Wires and Dots by : Paul Harrison
Download or read book Quantum Wells, Wires and Dots written by Paul Harrison and published by John Wiley & Sons. This book was released on 2011-09-26 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum Wells, Wires and Dots, 3rd Edition is aimed at providing all the essential information, both theoretical and computational, in order that the reader can, starting from essentially nothing, understand how the electronic, optical and transport properties of semiconductor heterostructures are calculated. Completely revised and updated, this text is designed to lead the reader through a series of simple theoretical and computational implementations, and slowly build from solid foundations, to a level where the reader can begin to initiate theoretical investigations or explanations of their own.
Book Synopsis Proceedings of the First International Symposium on Long Wavelength Infrared Detectors and Arrays: Physics and Applications by : Farhad Radpour
Download or read book Proceedings of the First International Symposium on Long Wavelength Infrared Detectors and Arrays: Physics and Applications written by Farhad Radpour and published by . This book was released on 1995 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Intersubband Transitions in Quantum Wells: Physics and Device Applications II by :
Download or read book Intersubband Transitions in Quantum Wells: Physics and Device Applications II written by and published by Academic Press. This book was released on 1999-10-25 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intersubband Transitions in Quantum Wells: Physics and Device Applications II
Book Synopsis Self-Assembled Nanostructures by : Jin Zhang
Download or read book Self-Assembled Nanostructures written by Jin Zhang and published by Springer Science & Business Media. This book was released on 2006-04-11 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanostructures refer to materials that have relevant dimensions on the nanometer length scales and reside in the mesoscopic regime between isolated atoms and molecules in bulk matter. These materials have unique physical properties that are distinctly different from bulk materials. Self-Assembled Nanostructures provides systematic coverage of basic nanomaterials science including materials assembly and synthesis, characterization, and application. Suitable for both beginners and experts, it balances the chemistry aspects of nanomaterials with physical principles. It also highlights nanomaterial-based architectures including assembled or self-assembled systems. Filled with in-depth discussion of important applications of nano-architectures as well as potential applications ranging from physical to chemical and biological systems, Self-Assembled Nanostructures is the essential reference or text for scientists involved with nanostructures.
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 1248 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Government Reports Annual Index by :
Download or read book Government Reports Annual Index written by and published by . This book was released on 1992 with total page 1400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Measuring the Universe by : George H. Rieke
Download or read book Measuring the Universe written by George H. Rieke and published by Cambridge University Press. This book was released on 2017-05-25 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy is an observational science, renewed and even revolutionized by new developments in instrumentation. With the resulting growth of multiwavelength investigation as an engine of discovery, it is increasingly important for astronomers to understand the underlying physical principles and operational characteristics for a broad range of instruments. This comprehensive text is ideal for graduate students, active researchers and instrument developers. It is a thorough review of how astronomers obtain their data, covering current approaches to astronomical measurements from radio to gamma rays. The focus is on current technology rather than the history of the field, allowing each topic to be discussed in depth. Areas covered include telescopes, detectors, photometry, spectroscopy, adaptive optics and high-contrast imaging, millimeter-wave and radio receivers, radio and optical/infrared interferometry, and X-ray and gamma-ray astronomy, all at a level that bridges the gap between the basic principles of optics and the subject's abundant specialist literature. Color versions of figures and solutions to selected problems are available online at www.cambridge.org/9780521762298.
Book Synopsis Germanium Silicon: Physics and Materials by :
Download or read book Germanium Silicon: Physics and Materials written by and published by Academic Press. This book was released on 1998-11-09 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise that this tradition will be maintained and even expanded.Reflecting the truly interdisciplinary nature of the field that the series covers, the volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in modern industry.
